Drying and gas or vapor contact with solids – Apparatus – For diverse operations on treated material
Reexamination Certificate
2002-09-11
2004-02-10
Lazarus, Ira S. (Department: 3749)
Drying and gas or vapor contact with solids
Apparatus
For diverse operations on treated material
C034S210000, C034S230000, C426S466000
Reexamination Certificate
active
06688018
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
This invention most generally relates to methods and apparatus for drying sliced and granular materials and small fruit crops with a heated airflow, and more particularly to distributed airflow containers and airflow circulation systems with simple open loop airflow circuits and complex open and closed loop airflow circuits for batch drying of diced, sliced or granular materials up to berry size to reduce the moisture content.
2. Background
The drying or reduction in moisture content of berries, cherries, grapes, nuts, whole fruits, sliced fruits, meats, and bulk materials provided in the form of granules or slices or small pieces is an old and well informed field of art. For example, the art of harvesting and processing coffee beans from tree-borne “cherries” to the green coffee bean of commerce consists of two principle methods, the “dry” method and the “wet” method. Either method must result in moisture content equivalent to one third or more of the bean's weight being removed, to produce a commercial product.
The dry method is the more ancient and rudimentary. The cherries are hand-picked all in one picking, washed, and sun-dried on drying ground or concrete slabs in thin layers, usually for a period of two to three weeks. The beans are heated by solar radiation from above and by secondary radiation from the already warmed concrete slab below, while natural circulation of relatively dry air over the top of the beans slowly leaches out the moisture. The beans ferment during the process, and are turned several times a day to promote even drying. They are covered at night to protect them from reabsorbing moisture during the night time dew point and temperature changes.
In the wet method, only the ripe cherries are picked in any one picking of a tree. It may take three to five sequential pickings in a season over the time it takes between the earliest and the latest cherries to ripen. After the cherries are washed, the outside fruit pulp is removed by machines and the berries are then placed into large concrete tanks to ferment for twelve to twenty-four hours, then poured into concrete sluiceways or washing machines to be thoroughly washed in constantly running water. Then they are dried in much the same way as in the dry method, except that the drying time is shorter. These beans are then processed through hulling machines to remove the remaining layers of skin.
Problems with either method of this art include the inefficient, labor-intensive and lengthy sun-drying time of beans arranged on open air slabs. There have been introduced over the years, other manual, passive solar methods and devices attempting to promote and control air movement in combination with heat, to remove the moisture from bulk crops. Most typically, the beans or other materials being dried, are supported on a foramenous surface or in a container having at least foramenous bottom surface or screen, to permit a greater degree of circulation or air flow in contact with the underside as well as the topside of the bulk materials.
Various electrical powered and/or fuel-fired dryer systems have also been used to try to accelerate the drying time and prevent mold problems. There are many patents that describe related technologies and devices. Most of these alternatives add expense and complexity to an otherwise simple process. Failing to safeguard the beans from excess moisture, in particular the formation of mold during the drying process is crucial as the value of the crop drops dramatically if mold occurs. Over drying can also occur using accelerated methods; this also affects the quality and value of the crop. A sampling of the art of convective and low pressure air drying systems is included to provide context for the reader:
Stokes' U.S. Pat. No. 4,490,926 (1985) discloses a solar drying device and method for lumber, tobacco and grain. It includes a solar collector, a drying chamber, and a dehumidification system. The background section mentions solar heated kilns and dryers with easy access and containerized methods, wheeled vehicles or carts, for moving materials into and out of the dryer. Insulation and double glazing of light-admitting sheet materials is discussed, as is passing air between a drying chamber and a dehumidifying chamber. The focus is on drying and reusing the air.
Sutherland's U.S. Pat. No. 5,584,127 (1996) is a recent patent for a solar powered fruit dryer. The focus of the apparatus design is on recirculation of a portion of the drying gas. It refers to air circulating through perforated shelves (col. 4, line 32) upon which the materials are arranged. Column 4, line 60, describes the physical embodiment in some detail, including air flow volumes.
Andrassy's U.S. Pat. No. 5,001,846 (1991) is a solar drying apparatus with a translucent sloping top and means for evacuating the condensation from the moist air. The specification describes a perforated or porous tray on which the materials are arranged for drying. A solar powered fan forces drying air vertically through the porous tray.
Mullin's U.S. Pat. No. 4,099,338 (1978) shows an elaborate, solar-assisted dryer for tobacco, onions, titanium dioxide drying, polyester fiber setting, and roasting nuts and cereals. The focus appears to be on ratios of solar heated makeup air in the circulation system to save fuel. The material is dried on a foraminous conveyor belt.
O'Hare's U.S. Pat. No. 4,501,074 (1985) is a convection powered solar food dryer that discloses a solar collector on the inlet side for heating intake air, and a vertical solar tower or column to accelerate the convection of warm air through the system by suction. The actual drying chamber can be removed from the solar devices at each end of the convection system. The materials are arranged on shelves in the drying chamber.
Steffen's U.S. Pat. No. 4,045,880 (1977) is a solar grain drying apparatus. It discloses a fan forced down draft eave inlet solar roof heating system, that then drives the drying air up through the perforated floor of the central drying chamber. The air is then exhausted upwards roof exhaust fans in the drying chamber ceiling.
Muller's U.S. Pat. No. 1,556,865 (1923) is a solar powered dryer system for vegetable matter, consisting of a series of circumferential racks with inlet perforations in the sidewalls and internal shelf brackets in the corners for holding drying shelves or trays. The racks are configured for interlocked stacking underneath a solar collector roof which has a central exhaust vent.
Pietraschke's U.S. Pat. No. 4,391,046 (1983) is a solar heated grain drying system featuring an inlet manifold receiving multiple collector pipes and a fan blowing the intake air up through a perforated floor in the drying chamber.
Sweeny's U.S. Pat. No. 278,199 (1883) is a coffee roaster showing perforated drums for containing the coffee beans, configured to revolve within a heated chamber. The drums are feed by hoppers through the ends. The drums use internal vanes to distribute the beans or other materials lengthwise, particularly for loading and unloading the drums. Heating is by other than solar means.
Danford's U.S. Pat. No. 4,263,721 (1981) is a tobacco curing and drying structure that is configured for adding makeup air, using a heat exchanger and means for partial recirculation.
The drying of coffee beans is exemplary of the prior art. The drying or dehydrating of fruits, nuts, vegetables and other food crops and naturally granular or crushed or sliced materials is a much frequented subject in the prior art. It is noteworthy that a sliced and dried piece of fruit has a significantly higher value than the freshly harvested product. While coffee and related bulk crops were the subject of the parent applications, the principles disclosed there are extended in both content and application in the disclosure that follows.
SUMMARY OF THE INVENTION
The invention in it's simplest form is a low pressure airflow dryer or dehydrator syste
Lazarus Ira S.
Maine & Asmus
O'Malley Kathryn S.
LandOfFree
Apparatus for bulk drying of sliced and granular materials does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus for bulk drying of sliced and granular materials, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus for bulk drying of sliced and granular materials will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3300986